Air pollution might help cause heart disease and strokes in older women, US researchers reported on Wednesday. They found women living in areas with high concentrations of tiny particles of air pollution were more prone to strokes, heart attacks and other forms of heart disease than those living where the air is cleaner.

"Our study provides evidence of the association between long-term exposure to air pollution and the incidence of cardiovascular disease," Dr. Joel Kaufman of the University of Washington at Seattle and colleagues wrote in their report, published in this week's New England Journal of Medicine. The team, working with the US government-funded Women's Health Initiative, studied the health records of nearly 66,000 women over the age of 50 across the United States.

"We assessed the women's exposure to air pollutants using the monitor located nearest to each woman's residence," the researchers wrote. Each time the concentration of particulates increased by 10 micrograms per cubic meter of air, a woman's risk of dying from heart disease rose by 76 percent, the researchers found.

The study "greatly expands our understanding of how fine particulate pollution affects health," Dr. Douglas Dockery and Dr. Peter Stone of Harvard University wrote in a commentary. "The magnitude of health effects may be larger than previously recognized," the researchers concluded.

Earlier studies had shown particulate pollution increases the death rate. The particles in question are so tiny that at least 400 laid end-to-end would be needed to cover 1 millimeter (0.04 inch). They come from burning fossil fuels.

The reason the particles increase the risk is not known for certain. Scientists suspect they may cause inflammation in the blood vessels and the lungs, prompting fatty deposits to build up and clog the arteries. Other air pollutants including sulfur dioxide, carbon monoxide, ozone and nitrogen dioxide, did not increase the heart attack risk, the study said.
(Por Gene Emery, Planet Ark, 01/02/2007)